Antimicrobial prescribing practices following publication of guidelines for the prevention of infections associated with combat-related injuries

A Retrospective Analysis of Combat Injury Patterns and Prehospital Interventions Associated with the Development of Sepsis

BACKGROUND

Combat injury related wound infections are common. Untreated, these wound infections may progress to sepsis and septic shock leading to increased morbidity and mortality rates. Understanding infectious complications, patterns, progression, and correlated prehospital interventions are vital to understand the development of sepsis. We aim to analyze demographics, injury patterns, and interventions associated with sepsis in battlefield settings.

MATERIALS AND METHODS

This is a secondary analysis of previously published data from the Department of Defense Trauma Registry (DoDTR) from 2007 to 2020. We searched for casualties diagnosed with sepsis (excluding line-sepsis) throughout their initial hospitalization. Regression models were used to seek associations.

RESULTS

Our initial request yielded 28,950 encounters, of which 25,654 (88.6%) were adults that met inclusion, including 243 patients (0.9%) diagnosed with sepsis. Patients included US military (34%), non-North Atlantic Treaty Organization (NATO) military (33%) and humanitarian (30%) groups. Patients diagnosed with sepsis had a significantly lower survival rate than non-septic patients (78.1% vs. 95.7%, p < 0.001). There was no significant difference in administration of prehospital antibiotics between septic and the general populations (10.6% vs. 12.3%, p = 0.395). Prehospital intraosseous access (OR 1.56, 95% CI 1.27-1.91, p = 0.207) and packed red cell administration (1.63, 1.24-2.15, 0.029) were the interventions most associated with sepsis.

CONCLUSIONS

Sepsis occurred infrequently in the DoDTR when evacuation from battlefield is not delayed, but despite increased intervention frequency, developing sepsis demonstrates a significant drop in survival rates. Future research would benefit from the development of risk mitigation measures.

Department of Defense Trauma Registry Infectious Disease Module Impact on Clinical Practice

BACKGROUND

The Joint Trauma System (JTS) is a DoD Center of Excellence for Military Health System trauma care delivery and the DoD's reference body for trauma care in accordance with National Defense Authorization Act for Fiscal Year 2017. Through the JTS, evidence-based clinical practice guidelines (CPGs) have been developed and subsequently refined to standardize and improve combat casualty care. Data are amassed through a single, centralized DoD Trauma Registry to support process improvement measures with specialty modules established as the registry evolved. Herein, we review the implementation of the JTS DoD Trauma Registry specialty Infectious Disease Module and the development of infection-related CPGs and summarize published findings on the subsequent impact of the Infectious Disease Module on combat casualty care clinical practice and guidelines.

METHODS

The DoD Trauma Registry Infectious Disease Module was developed in collaboration with the Infectious Disease Clinical Research Program (IDCRP) Trauma Infectious Disease Outcomes Study (TIDOS). Infection-related information (e.g., syndromes, antibiotic management, and microbiology) were collected from military personnel wounded during deployment June 1, 2009 through December 31, 2014 and medevac'd to Landstuhl Regional Medical Center in Germany before transitioning to participating military hospitals in the USA.

RESULTS

To support process improvements and reduce variation in practice patterns, data collected through the Infectious Disease Module have been utilized in TIDOS analyses focused on assessing compliance with post-trauma antibiotic prophylaxis recommendations detailed in JTS CPGs. Analyses examined compliance over three time periods: 6 months, one-year, and 5 years. The five-year analysis demonstrated significantly improved adherence to recommendations following the dissemination of the 2011 JTS CPG, particularly with open fractures (34% compliance compared to 73% in 2013-2014). Due to conflicting recommendations regarding use of expanded Gram-negative coverage with open fractures, infectious outcomes among patients with open fractures who received cefazolin or expanded Gram-negative coverage (cefazolin plus fluoroquinolones and/or aminoglycosides) were also examined in a TIDOS analysis. The lack of a difference in the proportion of osteomyelitis (8% in both groups) and the significantly greater recovery of Gram-negative organisms resistant to aminoglycosides or fluoroquinolones among patients who received expanded Gram-negative coverage supported JTS recommendations regarding the use of cefazolin with open fractures. Following recognition of the outbreak of invasive fungal wound infections (IFIs) among blast casualties injured in Afghanistan, the ID Module was refined to capture data (e.g., fungal culture and histopathology findings, wound necrosis, and antifungal management) needed for the TIDOS team to lead the DoD outbreak investigation. These data captured through the Infectious Disease Module provided support for the development of a JTS CPG for the prevention and management of IFIs, which was later refined based on subsequent TIDOS IFI analyses.

CONCLUSIONS

To improve combat casualty care outcomes and mitigate high-consequence infections in future conflicts, particularly in the event of prolonged field care, expansion, refinement, and a mechanism for sustainability of the DoD Trauma Registry Infectious Disease Module is needed to include real-time surveillance of infectious disease trends and outcomes.

Antimicrobial Stewardship Challenges in the Deployed Setting

INTRODUCTION

Up to 34% of combat trauma injuries are complicated by infection with multidrug-resistant organisms. Overutilization of antibiotics has been linked to increased multidrug-resistant organisms in combat-injured patients. Antimicrobial stewardship efforts at deployed medical treatment facilities have been intermittently reported; however; a comprehensive assessment of antimicrobial stewardship practices has not been performed.

MATERIALS AND METHODS

A survey tool was modified to include detailed questions on antimicrobial stewardship practices at medical treatment facilities. A Joint Service, multidisciplinary team conducted on-site assessments and interviews to assess the status of antimicrobial stewardship best practices, with particular emphasis on antibiotic prophylaxis in combat injured, in the U.S. Central Command operational theaters. Limitations to implementing stewardship to the national standards were explored thematically.

RESULTS

Nine Role 1, 2, and 3 medical facilities representing the range of care were assessed on-site. A total of 67% of the sites reported a formal antimicrobial stewardship program and 56% of the sites had an assigned head of antimicrobial stewardship. No military personnel in theater received training on antimicrobial stewardship and laboratory assets were limited. Personnel at these sites largely had access to Joint Trauma System guidelines describing antimicrobial prophylaxis for combat injured (89%), yet infrequently received feedback on their implementation and adherence to these guidelines (11%).

CONCLUSIONS

Antimicrobial stewardship programs in theater are in the early stages of development in theater. Areas identified for improvement are access to expertise, development of a focus on high-impact lines of effort, laboratory support, and the culture of antimicrobial prescribing. Risks can be mitigated through theater level formalization of efforts, expert mentoring through telehealth, and a focus on implementation and adherence and feedback to national guidelines.

Antibiotic Practice Patterns for Extremity Wound Infections among Blast-Injured Subjects

INTRODUCTION

We examined antibiotic management of combat-related extremity wound infections (CEWI) among wounded U.S. military personnel (2009-2012).

METHODS

Patients were included if they sustained blast injuries, resulting in ≥1 open extremity wound, were admitted to participating U.S. hospitals, developed a CEWI (osteomyelitis or deep soft-tissue infections) within 30 days post-injury, and received ≥3 days of relevant antibiotic (s) for treatment.

RESULTS

Among 267 patients, 133 (50%) had only a CEWI, while 134 (50%) had a CEWI plus concomitant non-extremity infection. In the pre-diagnosis period (4-10 days prior to CEWI diagnosis), 95 (36%) patients started a new antibiotic with 28% of patients receiving ≥2 antibiotics. During CEWI diagnosis week (±3 days of diagnosis), 209 (78%) patients started a new antibiotic (71% with ≥2 antibiotics). In the week following diagnosis (4-10 days after CEWI diagnosis), 121 (45%) patients started a new antibiotic with 39% receiving ≥2 antibiotics. Restricting to ±7 days of CEWI diagnosis, patients commonly received two (35%) or three (27%) antibiotics with frequent combinations involving carbapenem, vancomycin, and fluoroquinolones.

CONCLUSIONS

Substantial variation in antibiotic prescribing patterns related to CEWIs warrants development of combat-related clinical practice guidelines beyond infection prevention, to include strategies to reduce the use of unnecessary antibiotics and improve stewardship.

Antimicrobial Prophylaxis with Combat-Related Open Soft-Tissue Injuries

INTRODUCTION

All Department of Defense (DoD) guidance documents recommend cefazolin or clindamycin as post-trauma antibiotic prophylaxis for open soft-tissue injuries. Although not advocated, some patients with open soft-tissue injuries also received expanded Gram-negative coverage (EGN) prophylaxis based on the judgment of front-line trauma providers. During the study period, revised guidelines in 2011/2012 re-emphasized recommendations for using cefazolin or clindamycin, and stewardship efforts in the DoD trauma community aimed to reduce the practice of adding EGN to guideline-recommended antibiotic prophylaxis. Our objective was to examine antibiotic utilization among wounded military personnel with open extremity soft-tissue injuries over a 5-yr period and assess the impact on infectious outcomes in patients who received EGN prophylaxis versus guideline-directed prophylaxis.

METHODS

The study population included military personnel with open extremity soft-tissue injuries sustained in Iraq and Afghanistan (2009-2014) who transferred to participating hospitals in the USA following medical evacuation. The analysis was restricted to patients who were hospitalized for at least seven days at a U.S. facility and excluded those who sustained open fractures. Post-trauma antibiotic prophylactic regimens were defined as narrow if they followed recommended guidance (e.g., IV cefazolin or clindamycin) or EGN coverage when the narrow regimen also included fluoroquinolones and/or aminoglycosides. Intravenous amoxicillin-clavulanate, which is commonly used at non-U.S. coalition theater hospitals, was also classified as narrow because it conformed to coalition antibiotic prophylaxis guidelines. This study was approved by the Infectious Disease Institutional Review Board of the Uniformed Services University of the Health Sciences.

RESULTS

A total of 287 wounded personnel with open soft-tissue injuries were assessed, of which 212 (74%) received narrow prophylaxis and 75 (26%) received EGN coverage (p < 0.001). Among patients in the narrow prophylaxis group, 81% were given cefazolin and/or clindamycin, while 19% received amoxicillin-clavulanate. In the EGN group, 88% and 12% received a fluoroquinolone and aminoglycoside, respectively. Use of EGN coverage significantly declined during the study period from 39% in 2009-2010 to 11% in 2013-2014 (p < 0.001). Approximately 3% of patients who received a narrow regimen developed an extremity skin and soft-tissue infection, while there were no skin and soft-tissue infections among patients in the EGN coverage group. Nonetheless, this was not a significant difference (p = 0.345). In addition, the proportion of non-extremity infections was not significantly different between narrow and EGN regimen groups (11% and 15%, respectively). There were also no significant differences between the narrow and EGN regimen groups related to duration of hospitalization (median of 19 versus 20 d).

CONCLUSION

Use of non-guideline directed EGN-based post-trauma antibiotic prophylaxis does not improve infectious outcomes nor does it shorten hospital stay.

After the Battlefield: Infectious Complications among Wounded Warriors in the Trauma Infectious Disease Outcomes Study

INTRODUCTION

During recent wars in Iraq and Afghanistan, improved survivability in severe trauma corresponded with a rise in the proportion of trauma-related infections, including those associated with multidrug-resistant organisms (MDROs). Significant morbidity was reported in association with the infections. There is also concern regarding potential long-term impacts of the trauma-related infectious complications. Therefore, to meet the critical need of prospective collection of standardized infection-related data to understand the disease burden and improve outcomes of wounded personnel, the Trauma Infectious Disease Outcomes Study (TIDOS) was developed. Herein, we review accomplishments and key peer-reviewed findings of TIDOS.

METHODS

The TIDOS project is a multicenter observational study of short- and long-term infectious complications following deployment-related trauma. Wounded military personnel medevac'd to Landstuhl Regional Medical Center (LRMC; Germany) before transfer to a participating US military hospital between June 2009 and December 2014 were eligible for inclusion. An infectious disease module to supplement the Department of Defense Trauma Registry by collecting infection-related data from all trauma patients admitted to participating hospitals was developed. Specimens from trauma patients were also collected and retained in a microbiological isolate repository. During the initial hospitalization, patients were given the opportunity to enroll in a prospective follow-up cohort study. Patients who received Department of Veterans Affairs (VA) care were also given the opportunity to consent to ongoing VA follow-up.

RESULTS

A total of 2,699 patients transferred to participating military hospitals in the USA, of which 1,359 (50%) patients enrolled in the TIDOS follow-up cohort. In addition, 638 enrolled in the TIDOS-VA cohort (52% of TIDOS enrollees who entered VA healthcare). More than 8,000 isolates were collected from infection control surveillance and diagnostic evaluations and retained in the TIDOS Microbiological Repository. Approximately 34% of the 2,699 patients at US hospitals developed a trauma-related infection during their initial hospitalization with skin and soft-tissue infections being predominant. After discharge from the US hospitals, approximately one-third of TIDOS cohort enrollees developed a new trauma-related infection during follow-up and extremity wound infections (skin and soft-tissue infections and osteomyelitis) continued to be the majority. Among TIDOS cohort enrollees who received VA healthcare, 38% developed a new trauma-related infection with the incident infection being diagnosed a median of 88 days (interquartile range: 19-351 days) following hospital discharge. Data from TIDOS have been used to support the development of Joint Trauma System clinical practice guidelines for the prevention of combat-related infections, as well as the management of invasive fungal wound infections. Lastly, due to the increasing proportion of infections associated with MDROs, TIDOS investigators have collaborated with investigators across military laboratories as part of the Multidrug-Resistant and Virulent Organisms Trauma Infections Initiative with the objective of improving the understanding of the complex wound microbiology in order to develop novel infectious disease countermeasures.

CONCLUSIONS

The TIDOS project has focused research on four initiatives: (1) blast-related wound infection epidemiology and clinical management; (2) DoD-VA outcomes research; (3) Multidrug- Resistant and other Virulent Organisms Trauma Infections Initiative; and (4) Joint Trauma System clinical practice guidelines and antibiotic stewardship. There is a continuing need for longitudinal data platforms to support battlefield wound research and clinical practice guideline recommendation refinement, particularly to improve care for future conflicts. As such, maintaining a research platform, such as TIDOS, would negate the lengthy time needed to initiate data collection and analysis.

Variation in Postinjury Antibiotic Prophylaxis Patterns Over Five Years in a Combat Zone

In 2008, a clinical practice guideline (CPG) was developed for the prevention of infections among combat casualties and was later revised in 2011. We evaluated utilization of antimicrobials within 48 hours following injury in the combat zone over a 5-year period (June 2009 through May 2014) with regard to number of regimens, type of antimicrobial, and adherence to the 2011 CPG. The study population consisted of 5,196 wounded military personnel. Open fractures and skin and soft-tissue injuries were the most frequent injuries. Closed injuries had the highest overall compliance (83%), whereas open fractures and maxillofacial injuries had significant improvement in compliance from 2009-2010 (34 and 50%, respectively) to 2013-2014 (73 and 76%, respectively; p < 0.05). Part of the improvement with open fractures was a significant reduction of expanded Gram-negative coverage (61% received it in 2009-2010 compared to 7% in 2013-2014; p < 0.001). Use of Gram-negative coverage with maxillofacial injuries also significantly declined (37-12%; p = 0.001). Being injured during 2011-2014 compared to 2009-2010 was associated with CPG compliance (p < 0.001), while high injury severity scores (≥10) and admission to the intensive care unit in Germany were associated with noncompliance (p < 0.001). Our analysis demonstrates an increasing trend toward CPG compliance with significant reduction of expanded Gram-negative coverage.

Early infectious outcomes after addition of fluoroquinolone or aminoglycoside to posttrauma antibiotic prophylaxis in combat-related open fracture injuries

BACKGROUND

We examined combat-related open extremity fracture infections as a function of whether posttrauma antimicrobial prophylaxis included expanded Gram-negative (EGN) coverage.

METHODS

Military personnel with open extremity fractures sustained in Iraq and Afghanistan (2009-2014) who transferred to participating hospitals in the United States were assessed. The analysis was restricted to patients with a U.S. hospitalization period of ≥7 days. Prophylaxis was classified as narrow (e.g., IV cefazolin, clindamycin, and/or amoxicillin-clavulanate) or EGN, if the prophylactic regimen included fluoroquinolones and/or aminoglycosides.

RESULTS

The study population included 1,044 patients, of which 585 (56%) and 459 (44%) received narrow and EGN coverage, respectively (p < 0.001). Skin and soft-tissue infections (SSTIs) were more common among patients who received narrow prophylaxis compared to EGN coverage (28% vs. 22%; p = 0.029), whereas osteomyelitis rates were comparable between regimens (8%). Similar findings were noted when endpoints were measured at 2 and 4 weeks postinjury. There was no significant difference related to length of hospitalization between narrow and EGN regimens (median: 34 and 32 days, respectively) or operating room visits (median: 5 and 4). A higher proportion of EGN coverage patients had Gram-negative organisms isolated that were not susceptible to fluoroquinolones and/or aminoglycosides (49% vs. 40%; p < 0.001). In a Cox proportional model, narrow prophylaxis was independently associated with an increased risk of extremity SSTIs (hazard ratio: 1.41; 95% confidence interval: 1.09-1.83).

DISCUSSION

Despite seeing a small benefit with EGN coverage related to a reduction of SSTIs, it does not decrease the risk of osteomyelitis, and there seems to be a cost of increased antibiotic resistance associated with use. Overall, our findings support the current post-combat trauma antibiotic prophylaxis guidelines, which recommend the use of cefazolin or clindamycin with open fractures.

LEVEL OF EVIDENCE

Prognostic/Epidemiological, Level II; Therapy, level IV.

Clinical practice guideline adherence during Operation Inherent Resolve

BACKGROUND

The Joint Trauma System (JTS) clinical practice guidelines (CPGs) contributed to the decrease in battlefield mortality over the past 15 years. However, it is unknown to what degree the guidelines are being followed in current military operations.

METHODS

A retrospective review was performed of all patients treated at three separate US Army Role II facilities during the first 10 months of Operation Inherent Resolve in Iraq. Charts were reviewed for patient demographics, clinical care, and outcomes. Charts were also reviewed for compliance with JTS CPGs and Tactical Combat Casualty Care recommendations.

RESULTS

A total of 114 trauma patients were treated during the time period. The mean age was 26.9 ± 10.1 years, 90% were males, and 96% were host nation patients. The most common mechanisms of injury were blast (49%) and gunshot (42%). Records were compliant with documenting a complete set of vitals in 58% and a pain score in 50% of patients. Recommendations for treatment of hypothermia were followed for 97% of patients. Tranexamic acid was given outside guidelines for 6% of patients, and for 40%, it was not determined if the guidelines were followed. Recommendations for initial resuscitative fluid were followed for 41% of patients. Recommendations for antibiotic prophylaxis were followed for 40% of intra-abdominal and 73% of soft tissue injuries. Recommendations for tetanus prophylaxis were followed for 90% of patients. Deep vein thrombosis prophylaxis was given to 32% of patients and contraindicated in 27%. The recommended transfusion ratio was followed for 56% of massive transfusion patients. Recommendations for calcium administration were followed for 40% of patients. When composite scores were created for individual surgeons, there was significant variability between surgeons with regard to adherence to guidelines.

CONCLUSIONS

There is significant deviation in the adherence to the CPGs.

LEVEL OF EVIDENCE

Epidemiologic study, level IV.

Multi-Drug-Resistant Gram-Negative Infections in Deployment-Related Trauma Patients

BACKGROUND

The contribution of multi-drug-resistant gram-negative bacilli infections (MDRGN-I) in patients with trauma is not well described. We present characteristics of MDRGN-Is among military personnel with deployment-related trauma (2009-2014).

PATIENTS AND METHODS

Data from the Trauma Infectious Disease Outcomes Study were assessed for infectious outcomes and microbial recovery. Infections were classified using standardized definitions. Gram-negative bacilli were defined as multi-drug-resistant if they showed resistance to ≥3 antibiotic classes or were producers of extended-spectrum β-lactamase or carbapenemases.

RESULTS

Among 2,699 patients admitted to participating U.S. hospitals, 913 (33.8%) experienced ≥1 infection event, of which 245 (26.8%) had a MDRGN-I. There were 543 MDRGN-I events (24.6% of unique 2,210 infections) with Escherichia coli (48.3%), Acinetobacter spp. (38.6%), and Klebsiella pneumoniae (8.4%) as the most common MDRGN isolates. Incidence of MDRGN-I was 9.1% (95% confidence interval [CI]: 8.0-10.2). Median time to MDRGN-I event was seven days with 75% occurring within 13 days post-trauma. Patients with MDRGN-Is had a greater proportion of blast injuries (84.1% vs. 62.5%; p < 0.0001), traumatic amputations (57.5% vs. 16.3%; p < 0.0001), and higher injury severity (82.0% had injury severity score ≥25 vs. 33.7%; p < 0.0001) compared with patients with either no infections or non-MDRGN-Is. Furthermore, MDRGN-I patients were more frequently admitted to the intensive care unit (90.5% vs. 48.5%; p < 0.0001), colonized with a MDRGN before infection (58.0% vs. 14.7%; p < 0.0001), and required mechanical ventilation (78.0% vs. 28.8% p < 0.0001). Antibiotic exposure before the MDRGN-I event was significantly higher across antibiotic classes except first generation cephalosporins and tetracyclines, which were very commonly used with all patients. Regarding outcomes, patients with MDRGN-Is had a longer length of hospitalization than the comparator group (53 vs. 18 days; p < 0.0001).

CONCLUSIONS

We found a high rate of MDRGN-I in our population characterized by longer hospitalization and greater injury severity. These findings inform treatment and infection control decisions in the trauma patient population.

Prevention of combat-related infections: antimicrobial therapy in battlefield and barrier measures in French military medical treatment facilities

Infection is a major complication associated with combat-related injuries. Beside immobilization, wound irrigation, surgical debridement and delayed coverage, post-injury antimicrobials contribute to reduce combat-related infections, particularly those caused by bacteria of the early contamination flora. In modern warfare, bacteria involved in combat-related infections are mainly Gram-negative bacteria belonging to the late contamination flora. These bacteria are frequently resistant or multiresistant to antibiotics and spread through the deployed chain of care. This article exposes the principles of war wounds antimicrobial prophylaxis recommended in the French Armed Forces and highlights the need for high compliance to hygiene standard precautions, adapted contact precautions and judicious use of antibiotics in French deployed military medical treatment facilities (MTF).

Adherence to published antimicrobial prophylaxis guidelines for wounded service members in the ongoing conflicts in Southwest Asia

In 2008, a clinical practice guideline (CPG) was developed for the prevention of infections among military personnel with combat-related injuries. Our analysis expands on a prior 6-month evaluation and assesses CPG adherence with respect to antimicrobial prophylaxis for U.S. combat casualties medically evacuated to Landstuhl Regional Medical Center over a 1-year period (June 2009 through May 2010), with an eventual goal of continuously monitoring CPG adherence and measuring outcomes as a function of compliance. We classified adherence to the CPG as receipt of recommended antimicrobials within 48 hours of injury. A total of 1106 military personnel eligible for CPG assessment were identified and 74% received antimicrobial prophylaxis. Overall, CPG compliance within 48 hours of injury was 75%. Lack of antimicrobial prophylaxis contributed 2 to 22% to noncompliance varying by injury category, whereas receipt of antibiotics other than preferred was 11 to 30%. For extremity injuries, antimicrobial prophylaxis adherence was 60 to 83%, whereas it was 80% for closed injuries and 68% for penetrating abdominal injuries. Overall, the results of our analysis suggest an ongoing need to improve adherence, monitor CPG compliance, and assess effectiveness.

Current concepts of prophylactic antibiotics in trauma: a review

Traumatic injuries cause 5.8 million deaths per year globally. Before the advent of antibiotics, sepsis was considered almost inevitable after injury. Today infection continues to be a common complication after traumatic injury and is associated with increases in morbidity and mortality and longer hospital stays. Research into the prevention of post-traumatic infection has predominantly focused on thoracic and abdominal injuries. In addition, because research on sepsis following musculoskeletal injuries has predominantly been on open fractures. There is a paucity of research into the prevention of soft tissue infections following traumatic injuries. This review analyses the evidence for the role of prophylactic antibiotics in the management of soft tissue injuries. Emphasis is placed on assessing the strength of the presented evidence according to the Oxford Level of Evidence scale.